ColStatDesc.cpp

port skew buster to Trafodion 1. add simplified TEST062 2. reuse cached partitioning expression when only doVarCharCast is the same as the when the expression is created in TableHashPartitioningFunction::createPartitioningExpressionImp(). 3. rework 4. fix a time monitor bug reporting incorrect processor time (CPU time computed from clock() calls) 5. comment out the assert on the size of NATable cache not decreasing. This is to fix regression failure with seabase/TEST020. Selva will check in a formal fix that allocates space for NATable objects from a single heap, and then reenables this assert check.